sedimentary
Chert Nodule
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 7 (Mohs scale), Color: Cream to yellowish-tan, Luster: Waxy to dull, Crystal Structure: Cryptocrystalline, Cleavage: None (conchoidal fracture)
Identified More sedimentary →
Explore Chert Nodule in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 7 (Mohs scale), Color: Cream to yellowish-tan, Luster: Waxy to dull, Crystal Structure: Cryptocrystalline, Cleavage: None (conchoidal fracture)
Formation & geological history
Formed in sedimentary environments through the chemical precipitation of silica or the replacement of carbonate minerals by silica-rich fluids. Often found embedded in limestone or chalk beds.
Uses & applications
Historically used for making stone tools (flintknapping); commercially used in construction aggregates and occasionally for lapidary work.
Geological facts
Chert is essentially the same mineral as flint, but the term 'flint' is usually reserved for dark grey/black varieties found in chalk. It is highly resistant to weathering.
Field identification & locations
Identify by its hardness (cannot be scratched by a steel nail) and characteristic curved (conchoidal) fractures where it has broken. Commonly found in riverbeds or eroded out of limestone cliffs.
More like this
Other sedimentary specimens
Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
fossil
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sandstone
Arenite
sedimentary
Quartz pebble
Silicon dioxide (SiO2)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary